mm, dax: make pmd_fault() and friends be the same as fault()

Instead of passing in multiple parameters in the pmd_fault() handler,
a vmf can be passed in just like a fault() handler. This will simplify
code and remove the need for the actual pmd fault handlers to allocate a
vmf. Related functions are also modified to do the same.

[dave.jiang@intel.com: fix issue with xfs_tests stall when DAX option is off]
  Link: http://lkml.kernel.org/r/148469861071.195597.3619476895250028518.stgit@djiang5-desk3.ch.intel.com
Link: http://lkml.kernel.org/r/1484085142-2297-7-git-send-email-ross.zwisler@linux.intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 87e11df..d3f589b 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -273,21 +273,20 @@ static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 	return result;
 }
 
-static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
-						pmd_t *pmd, unsigned int flags)
+static int
+ext4_dax_pmd_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
 	int result;
 	struct inode *inode = file_inode(vma->vm_file);
 	struct super_block *sb = inode->i_sb;
-	bool write = flags & FAULT_FLAG_WRITE;
+	bool write = vmf->flags & FAULT_FLAG_WRITE;
 
 	if (write) {
 		sb_start_pagefault(sb);
 		file_update_time(vma->vm_file);
 	}
 	down_read(&EXT4_I(inode)->i_mmap_sem);
-	result = dax_iomap_pmd_fault(vma, addr, pmd, flags,
-				     &ext4_iomap_ops);
+	result = dax_iomap_pmd_fault(vma, vmf, &ext4_iomap_ops);
 	up_read(&EXT4_I(inode)->i_mmap_sem);
 	if (write)
 		sb_end_pagefault(sb);